A fluorescent tube should always be replaced with the same diameter bulb unless the ballast is changed to a different type. The lamp holders are made of plastic, so be careful not to break them when replacing these bulbs. Turn off the light switch before replacing bulbs. If you have difficulty gripping the bulb, use rubber gloves.
To remove the bulb, gently rotate 1/4 turn in either direction. If they don’t turn easily, reverse the direction of rotation to see if it turns more easily. Increase pressure while rotating bulb until it is removed.
Insert a new bulb into the lamp holders. Make sure the bulb is all the way into the lamp holders and gently rotate 1/4 turn in either direction (bulbs usually have alignment marks to indicate proper rotation).
T12 fluorescent tubes are not made anymore because of poor energy efficiency. While these lamps are still in stock in some stores, replacing the ballast with a more efficient T8 electronic ballast could be a better choice.
Fluorescent Tubes are different than compact fluorescents because they are powered by a separate ballast to start up and operate the bulb. They have two common shapes, straight and u-
Color temperature range is 2700K to 6500K. Fluorescent tubes will reach full brightness right away, however a newly installed bulb will take a while to reach full brightness, especially when it is cold.